This thesis sought to develop a better understanding of the role impostor cognitions play in the emergence of occupational burnout. Impostor cognitions refer to the phenomenon where intelligent and successful people fear that they are not as competent as other people believe them to be. While impostor cognitions are common in the workplace domain, there is limited understanding of the impact on work-related psychological outcomes. Thus, I aimed to: (1) clarify the relationship between impostor cognitions and occupational burnout proposed in the existing literature (2) examine the mediating role of peer comparisons in the relationship between impostor cognitions and burnout and (3) investigate whether the availability of information that normalises failure provided by peers contributes to a reduction in the negative psychological impact of impostor cognitions. Two studies were conducted to examine these three aims. Study 1 was intended to initially explore the proposed relationships in a cross-sectional study conducted amongst 214 Australian academics. Study 2 sought to confirm the findings of Study 1 with a two-wave repeated measures design in a broad range of 155 Australian working professionals. The results demonstrated that impostor cognitions were directly related to the emotional exhaustion and professional efficacy burnout dimensions, but not cynicism. Both studies demonstrated the relationship between impostor cognitions and emotional exhaustion and professional efficacy occurred indirectly via peer comparisons with colleagues. In contrast to predictions, information that normalises professional failures provided by peers did not moderate the relationship between impostor cognitions and peer comparisons. Implications for workplace interventions as well as suggestions for future research are discussed.